Medical devices have been implanted in patients to perform a variety of tasks. For example, programmable pulse generating systems are used to treat chronic pain by providing electrical stimulation pulses from an epidural electrode array placed near a patient's spine. Such Spinal Cord Stimulation (SCS) is useful for reducing pain in certain populations of patients. SCS systems typically include one or more electrodes connected to one or more connectors of an External Pulse Generator (EPG) or an Implanted Pulse Generator (IPG) via leads. In the case of an EPG, the lead must be connected to the EPG via an exit from the body. The pulse generator, whether internal or external, generates pulses that are typically delivered to the dorsal column fibers within the spinal cord through the electrodes which are implanted along or near the dura of the spinal cord. In a typical situation, the attached leads exit the spinal cord and are tunneled around the torso of the patient to a subcutaneous pocket where the IPG is implanted, or the wires exit the patient for connection to the EPG.
U.S. Pat. Nos. 7,537,474 and 6,895,876, incorporated herein by reference, disclose a connector solution for an implantable pulse generator (IPG) utilizing a coiled spring inside a contact block. The ends of the spring are welded together yielding a torus shape through which the in-line lead is inserted. The spring coils cant to conform to the contact ring of an IPG lead, thus making electrical contact. Each coil which contacts both the lead and the block forms a separate redundant electrical contact.
However, more accurate positioning of seals and electrical contact locations than are current available would be desirable. Furthermore, it would be useful to provide IPG devices with multiple lead ports that have contact stacks that are assembled as a single unit, and tested in a single fixture before final assembly of the IPG, to determine that all channels have electrical continuity to inserted pin(s) that represents a connection end of a stimulation lead.